MOSCOW (Reuters) - Moody's downgrade of Russia's sovereign rating was based on "factors of a political character," Russia's Finance Minister Anton Siluanov said early on Saturday following news that Moody's had cut the rating to below investment grade.

Siluanov also said that the downgrade was based on "unrealistic" forecasts with "no analogies", as the agency had made pessimistic assumptions that went well beyond forecasts by the IMF, World Bank and international banks.

He said the downgrade would not have a serious additional impact on the capital market as Russia's local currency rating remains at the investment grade level of BBB-. Local treasury bonds are currently seen by Russia as the only source of borrowing, Siluanov said.